Abstract：Excessive use of acetaminophen (APAP) can promote liver oxidative stress and cause liver damage. Forsythiaside A (FA), as the phenylethanol glycoside active component of the Chinese herb Forsythia, may have a hepatoprotective effect. To investigate the effect of FA on APAP-induced oxidative stress, C57BL/6 mice (Mus musculus) and alpha mouse liver 12 (AML12) cells were randomly divided into 4 groups: Blank control (NC), APAP-induced liver injury group (APAP), FA control group (FA), and FA treatment group (APAP+FA). Serum and cell supernatants were analyzed for alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity to determine the effective concentration of FA for treating APAP-induced liver injury. Levels of superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), and hydrogen peroxide (H2O2) in mouse liver tissue were measured, and pathological changes in liver tissue were observed to explore the therapeutic effect of FA on APAP-induced liver injury. A pregnane X receptor (PXR) overexpression plasmid was constructed, and C57BL/6 mice and AML12 cells were divided into 5 groups: normal control (NC), APAP-induced liver injury (APAP), APAP+PXR overexpression (APAP+PXR(OE)), FA treatment (APAP+FA), and FA treatment with PXR overexpression (APAP+FA+PXR(OE)). The effects of FA on SOD activity, GSH, MDA, H2O2, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) content, PXR protein and gene expression levels, and liver pathology were observed, and a rescue experiment was designed to verify the potential mechanism. The results showed that FA significantly reduced ALT and AST activity, as well as MDA and H2O2 content in APAP model mice (P<0.05), increased SOD activity and GSH content (P<0.05), and improved liver tissue pathology. FA also significantly reduced MDA, H2O2 content, and TNF-α, IL-1β, IL-6 levels (P<0.05), and increased SOD activity and GSH content (P<0.05) by inhibiting PXR. In conclusion, FA ameliorated oxidative stress by inhibiting PXR, thereby exerting a protective effect against APAP-induced liver injury. This study provides new ideas for the treatment of drug-induced liver injury and a theoretical foundation for the hepatoprotective effect of FA through inhibiting PXR.
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